pearl perch

Perciformes

The Perciformes, also called the Percomorphi or Acanthopteri, include about 40% of all bony fish and are the largest order of vertebrates. The name Perciformes means perch-like. They belong to the ray-finned fish and comprise over 7000 different species, with varying shapes and sizes, found in almost all aquatic environments. They are also the most variably sized order of vertebrates, ranging from the 7mm (0.3 in) Schindleria brevipinguis to the 5m (16.5 ft) large Makaira species. They first appeared and diversified in the Late Cretaceous.
Perciform fish typically have dorsal and anal fins divided into anterior spiny and posterior soft-rayed portions, which may be partially or completely separated. There are usually pelvic fins with one spine and up to five soft rays, either positioned by the throat or under the belly. Scales are usually ctenoid in form, though sometimes they are cycloid or otherwise modified. Various other, more technical characters define the group.

Classification is controversial. As traditionally defined the Perciformes are almost certainly paraphyletic. Other orders that should possibly be included as suborders are the Scorpaeniformes, Tetraodontiformes, and Pleuronectiformes. Of the presently recognized suborders several may be paraphyletic as well.